a) Field of the Invention
The present invention relates to a thermosiphon for transferring cooling energy from a refrigerating machine to a portion to be cooled.
b) Prior Art
Conventional thermosiphon of this type comprises a closed fluid system in which is enclosed a working fluid, said closed fluid system being constructed of a condenser, a liquid pipe connected to the condenser, an evaporator connected to the liquid pipe, and a gas pipe which is connected to the evaporator and returns to said condenser. In such conventional thermosiphon, the working fluid is deprived of heat at the condenser attached to a refrigerating machine so that the fluid is condensed, and then the fluid thus condensed flows down through the liquid pipe to reach the evaporator, where the working fluid deprives a portion to be cooled of latent heat of evaporation, so that it is evaporated to thereby go up through the gas pipe until it reaches the condenser. This cycle is operated by the difference in liquid level between the working fluid flowing down through the liquid pipe and the working fluid in the gas pipe.
According to such conventional thermosiphon, however, cooling energy from the refrigerating machine is liable to cool not only the condenser but also the respective connecting ends of the gas pipe and the liquid pipe, and thus the working fluid is condensed not only in the condenser but also in the liquid pipe and the upper portion of the gas pipe. In the liquid pipe, the working fluid is little condensed, as it is already almost condensed in the condenser. In the gas pipe, however, the condensed working fluid flows back and returns to the evaporator, and thus the amount of the working fluid that is to be condensed in the condenser and then to flow down through the liquid pipe is liable to be decreased by that amount. As a result, the liquid level in the liquid pipe is likely to be lowered, while that in the gas pipe is likely to be raised.
Further, as the liquid pipe is formed thinner than the gas pipe, the condensed working fluid is likely to overflow from the condenser so that it flows backward from the gas pipe to the evaporator, in the event that the condenser is overcooled for some reason. As above mentioned, the circulation fluid system of the working fluid is operated by the difference in liquid level between the working fluid flowing down the liquid pipe and the working fluid in the gas pipe. Accordingly, small difference in liquid level provides an obstruction to the above fluid system, and thus the circulation efficiency is likely to be lowered. Furthermore, there is another problem that vibration from the refrigerating machine is likely to be transferred to the evaporator, even to an object to be cooled, via the gas pipe or the liquid pipe, to thereby adversely affect the object. As the gas pipe is formed thicker than the liquid pipe, more vibration from the refrigerating machine is transferred to the evaporator via the gas pipe than via the liquid pipe.
Accordingly, it is a main object of the present invention to provide a thermosiphon for refrigerating machine which can cool something without the circulation system of the working fluid being choked.
It is another object of the present invention to provide a thermosiphon for refrigerating machine which can transfer the least possible vibration from the refrigerating machine to a portion to be cooled.
To attain the above objects, there is provided a thermosiphon for refrigerating machine, in accordance with a first aspect of the invention, comprising: a condenser provided in a cooling portion of the refrigerating machine, a liquid pipe connected to the condenser; an evaporator connected to the liquid pipe for depriving an object of heat; a gas pipe connected to the evaporator, said gas pipe extending back to said condenser; a working fluid which is filled in a circulation fluid system defined by said condenser, liquid pipe, evaporator and gas pipe; and a reverse-flow suppressing portion formed in a part of the gas pipe in the vicinity of said condenser, said reverse-flow suppressing portion including a riser pipe, positioned in a higher position than said condenser.
Thus, even if the working fluid is condensed in the reverse-flow suppressing portion due to the cooling energy from the condenser being transferred thereto, the condensed working fluid can be prevented from flowing back through the gas pipe into the evaporator, as the reverse-flow suppressing portion is provided in a higher position than the condenser, thereby ensuring the flowing down of the working fluid into the condenser. Further, as the distance from the condenser that is in contact with the refrigerating machine and the evaporator is elongated due to the reverse-flow suppressing portion being provided, the vibration transferred from the refrigerating machine to the evaporator is decreased by that elongated distance.
Further, there is also provided a thermosiphon for refrigerating machine from another aspect of the invention, wherein the thermosiphon according to the first aspect of the invention further comprises a damper portion which is formed by bending said gas pipe and/or said liquid pipe into the form of a wave or a coil.
Thus, the liquid pipe and/or the gas pipe is elongated by providing such damper portion, which in turn means that the distance from the condenser that is in contact with the refrigerating machine and the evaporator is elongated, thereby decreasing the vibration transferred from the refrigerating machine to the evaporator.
Furthermore, there is also provided a thermosiphon for refrigerating machine from a further aspect of the invention, wherein the gas pipe provided at a top side is always higher or at least even with said evaporator in said fluid passage. Accordingly, even though the liquid pipe and/or the gas pipe are/is formed with the waveform-shaped damper portion, yet the top side of the gas pipe is higher, or at least even with the evaporator so that the flowing-down of the condensed working fluid into the evaporator is insured, without staying in the course of the damper portion.